diff --git a/dartwrf/assim_synth_obs.py b/dartwrf/assim_synth_obs.py
index 2c7e4aaf26b76fbdabfb4b8b2a4766e18b6d9c52..d006be6cad92324569d9cd67db0a1174eb0d22cc 100755
--- a/dartwrf/assim_synth_obs.py
+++ b/dartwrf/assim_synth_obs.py
@@ -481,7 +481,7 @@ def set_obserr_assimilate_in_obsseqout(obsseqout, outfile="./obs_seq.out"):
             # overwrite with user-defined values
             obsseqout.df.loc[mask_kind, 'variance'] = obscfg["error_assimilate"]**2
 
-    obsseqout.to_dart(outfile+'2')
+    obsseqout.to_dart(outfile)
 
 
 if __name__ == "__main__":